On 22.06.2018 [10:21:19 +0800], Fam Zheng wrote: > On Thu, 06/21 15:21, Nishanth Aravamudan wrote: > > laio_init() can fail for a couple of reasons, which will lead to a NULL > > pointer dereference in laio_attach_aio_context(). > > > > To solve this, add a aio_setup_linux_aio() function which is called > > early in raw_open_common. If this fails, propagate the error up. The > > signature of aio_get_linux_aio() was not modified, because it seems > > preferable to return the actual errno from the possible failing > > initialization calls. > > > > Add an assert that aio_get_linux_aio() cannot return NULL. > > > > Signed-off-by: Nishanth Aravamudan <naravamu...@digitalocean.com> > > --- > > Changes from v2 -> v3 (thanks to Eric Blake and Kevin Wolf for review): > > > > Use a boolean false rather than 0 in assignment to use_linux_aio. > > Drop ending '.' from error_report() calls. > > Fix typo in commit message (propogates -> propagates). > > Move aio_setup_linux_aio call to raw_open_common. > > > > Changes from v1 -> v2 (thanks to Kevin Wolf for review): > > > > Rather than affect virtio-scsi/blk at all, make all the changes internal > > to file-posix.c. Thanks to Kevin Wolf for the suggested change. > > > > block/file-posix.c | 17 ++++++++++++----- > > block/linux-aio.c | 15 ++++++++++----- > > include/block/aio.h | 3 +++ > > include/block/raw-aio.h | 2 +- > > stubs/linux-aio.c | 2 +- > > util/async.c | 16 +++++++++++++--- > > 6 files changed, 40 insertions(+), 15 deletions(-) > > > > diff --git a/block/file-posix.c b/block/file-posix.c > > index 07bb061fe4..6a1714d4a8 100644 > > --- a/block/file-posix.c > > +++ b/block/file-posix.c > > @@ -545,11 +545,18 @@ static int raw_open_common(BlockDriverState *bs, > > QDict *options, > > > > #ifdef CONFIG_LINUX_AIO > > /* Currently Linux does AIO only for files opened with O_DIRECT */ > > - if (s->use_linux_aio && !(s->open_flags & O_DIRECT)) { > > - error_setg(errp, "aio=native was specified, but it requires " > > - "cache.direct=on, which was not specified."); > > - ret = -EINVAL; > > - goto fail; > > + if (s->use_linux_aio) { > > + if (!(s->open_flags & O_DIRECT)) { > > + error_setg(errp, "aio=native was specified, but it requires " > > + "cache.direct=on, which was not specified."); > > + ret = -EINVAL; > > + goto fail; > > + } > > + ret = aio_setup_linux_aio(bdrv_get_aio_context(bs)); > > + if (ret != 0) { > > + error_setg(errp, "Unable to setup native AIO context."); > > + goto fail; > > + } > > } > > #else > > if (s->use_linux_aio) { > > diff --git a/block/linux-aio.c b/block/linux-aio.c > > index 88b8d55ec7..4d799f85fe 100644 > > --- a/block/linux-aio.c > > +++ b/block/linux-aio.c > > @@ -470,28 +470,33 @@ void laio_attach_aio_context(LinuxAioState *s, > > AioContext *new_context) > > qemu_laio_poll_cb); > > } > > > > -LinuxAioState *laio_init(void) > > +int laio_init(LinuxAioState **linux_aio) > > { > > + int rc; > > LinuxAioState *s; > > > > s = g_malloc0(sizeof(*s)); > > - if (event_notifier_init(&s->e, false) < 0) { > > + rc = event_notifier_init(&s->e, false); > > + if (rc < 0) { > > It would be nice if the error message could distinguish this error... > > > goto out_free_state; > > } > > > > - if (io_setup(MAX_EVENTS, &s->ctx) != 0) { > > + rc = io_setup(MAX_EVENTS, &s->ctx); > > + if (rc != 0) { > > ... from this one. And it also makes sense to propagate the errno back with > error_setg_errno. > > To do this, add an "Error **errp" parameter to the function and you > can keep the return type (LinuxAioState *).
Thank you for this suggestion! I will send out a v4 with this and your other feedback integrated. -Nish